What causes the red reflection in dogs' eyes and is it a cause for concern?

The red reflection in dogs' eyes is caused by light reflecting off the blood vessels in the back of the eye. This is known as the tapetum lucidum, which helps improve their night vision. In most cases, this is not a cause for concern. However, if the red reflection is consistently off-center or accompanied by other symptoms like vision problems or eye discharge, it may indicate an underlying health issue and should be checked by a veterinarian.